Self Check 6.7 - 6.13

Natural gas is often priced in units of dollars per therm. One therm equals 100,000 BTUs. A certain family uses 600 therms of energy to heat its home annually using a natural gas furnace that is 80 percent efficient. The family is considering replacing its current furnace with one that is 96 percent efficient. Assuming the cost of a therm is $0.30, which of the following would be the family's annual savings in the cost of home heating?

$28.80

In many parts of the United States, homeowners use a significant portion of their energy budget to heat their home in the winter. It has been determined that lowering a thermostat by 3°F in the winter can reduce the energy costs by about 10 percent in many homes. An individual homeowner lowers their thermostat by 3 degrees exactly halfway through the billing period. For the month that the thermostat was lowered, the heating bill was $95. How much money did the family save in the month in which they lowered the thermostat setting halfway through the billing period?

$5.00

The largest hydroelectric dam in the world is located on one of the world's longest rivers in this area.

(E)

If an incandescent lightbulb used for lighting has an efficiency rating of 5 percent, then for every 1.00 joule of electrical energy consumed by the bulb, which of the following is produced?

0.05 joules of light energy

An individual has been driving a passenger vehicle to work, averaging 60 miles a week in a car that averages 22 miles per gallon. The individual plans to purchase a hybrid vehicle that averages 50 miles per gallon. If the individual drives to work 50 weeks a year, how much gas will they save if they switch to a hybrid vehicle for their commute?

76 gallons

Which of the following would be the best location for a wind farm with ten industrial turbines?

Arranged uniformly on a local farm that has fields and pastureland for dairy and grain production

Which of the following best explains the process of electricity generation in a hydrogen fuel cell?

At the anode, hydrogen is oxidized and electrons flow in a circuit to the cathode. At the cathode, oxygen reacts with the hydrogen to produce water. Water and heat are by-products of the reaction.

Directions: Select the choice that best fits each statement. The following question(s) refer to the following energy sources. Biomass Wind Tidal energy Nuclear fission Sunlight The source whose use is a direct cause of deforestation

Biomass

In the majority of less developed countries, the major source of energy for domestic use is which of the following?

Biomass

Which of the following best describes an advantage of burning biomass rather than burning fossil fuels in developing countries?

Biomass production is cheaper than fossil fuel extraction, making it more readily available for use.

Which of the following accurately describes a fuel cell vehicle?

Fuel cell vehicles use hydrogen to generate electricity that runs the motor.

Directions: Select the choice that best fits each statement. The following questions(s) refer to the following sources of energy. (A) Photovoltaics (B) Geothermal (C) Biomass (D) Hydroelectric (E) Hydrogen fuel Drawbacks include noise and the release of corrosive chemicals

Geothermal

Which of the following energy sources is not derived directly or indirectly from solar energy?

Geothermal

Which of the following best describes a disadvantage of geothermal energy production?

Geothermal energy implementation in homes and businesses has a high upfront cost, and electricity is needed to operate pumps.

Economic benefits of building large dams include which of the following? I. Storage of water for agriculture and domestic use II. Controlling floods upstream III. Production of renewable energy

I and III only

Which of the following describes the best strategy for mitigating this potential problem?

Installing effective ventilation systems in dwellings

Which of the following is a true statement about passive solar heating?

It is based in part on the principle of the greenhouse effect.

If peak electricity use occurs around 2p.m. in the Los Angeles area and avoiding brownouts is more important to the installers of the PV panels than annual energy output, which of the following PV panel systems would be best to use in the area?

No tracking, tilted east

If peak electricity use occurs around 2p.m. in the Los Angeles area and avoiding brownouts is more important to the installers of the PV panels than annual energy output, which of the following PV panel systems would be best to use in the area?

No tracking, tilted west

Which of the following best describes a benefit of increasing the number of offshore wind farms rather than onshore wind farms?

Offshore winds farms will produce up to three times as much electricity as wind farms on land because of increased wind speeds offshore.

Which of the following statements is best supported by the data shown in the graph?

PV panels that can track the Sun and are constantly moving to always directly face the Sun produce the most electricity daily and annually.

Directions: Select the choice that best fits each statement. The following questions(s) refer to the following sources of energy. (A) Photovoltaics (B) Geothermal (C) Biomass (D) Hydroelectric (E) Hydrogen fuel Converts solar energy directly into electrical energy

Photovoltaics

Which of the following is a way for the government to encourage efficient energy use?

Requiring higher fuel economy standards for new cars

Directions: Select the choice that best fits each statement. The following question(s) refer to the following energy sources. Biomass Wind Tidal energy Nuclear fission Sunlight The source that is converted directly into electrical energy by photovoltaic cells

Sunlight

Construction of a solar power plant is proposed for a desert area near a school. A student has hypothesized that the shade cast by the solar panels will increase the mortality of creosote bush, a native desert plant in the area. Before construction begins, what experimental data should the student collect in order to eventually test the hypothesis?

The direct sunlight received by creosote bush in the desert area (in kWh/m2) during a 12-month period

Which of the following best describes how the use of hydrogen fuel negatively impacts the environment?

The energy needed to produce the hydrogen fuel may come from fossil fuels, whose use contributes to ocean acidification and global climate change.

Which of the following statements about geothermal energy is accurate?

The location of geothermal energy sources ranges from short distances below ground to miles below the surface.

Which of the following best describes the method of vehicle transport that is the most environmentally sustainable?

The use of a vehicle powered by hydrogen fuel cells because there are no carbon emissions

Which of the following is a drawback to using biofuels, such as ethanol, as a fuel source?

There is high energy investment in producing and processing the crops needed for ethanol production.

Which of the following is the most practical solution to maximizing energy production at wind farms while minimizing the risk to wildlife?

Turn off turbines during periods of maximum migration.

A major limitation of using photovoltaic cells to generate electricity is that they

do not produce as much electricity on cloudy days

Geothermal energy plants are a viable alternative energy source because they

use the heat from Earth's interior to create steam that is used to generate electricity and then can be pumped back into the ground